title: Interdomain dynamics explored by paramagnetic NMR.
abstract: An ensemble-based approach is presented to explore the conformational space sampled by a multidomain protein showing moderate interdomain dynamics in terms of translational and rotational motions. The strategy was applied on a complex of calmodulin (CaM) with the IQ-recognition motif from the voltage-gated calcium channel Ca(v)1.2 (IQ), which adopts three different interdomain orientations in the crystal. The N60D mutant of calmodulin was used to collect pseudocontact shifts and paramagnetically induced residual dipolar couplings for six different lanthanide ions. Then, starting from the crystal structure, pools of conformations were generated by free MD. We found the three crystal conformations in solution, but four additional MD-derived conformations had to be included into the ensemble to fulfill all the paramagnetic data and cross-validate optimally against unused paramagnetic data. Alternative approaches led to similar ensembles. Our "ensemble" approach is a simple and efficient tool to probe and describe the interdomain dynamics and represents a general method that can be used to provide a proper ensemble description of multidomain proteins.
authors.affiliation: NMR Based Structural Biology, Max Planck Institute for Biophysical Chemistry , Am Fassberg 11 37077 Göttingen, Germany.
authors.forename: Luigi
authors.initials: L
authors.lastname: Russo
authors.forename: Mitcheell
authors.initials: M
authors.lastname: Maestre-Martinez
authors.forename: Sebastian
authors.initials: S
authors.lastname: Wolff
authors.forename: Stefan
authors.initials: S
authors.lastname: Becker
authors.forename: Christian
authors.initials: C
authors.lastname: Griesinger
mesh_terms: D020746:Calcium Channels, L-Type / Q000737:chemistry* / Q000378:metabolism; D002147:Calmodulin / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D056004:Molecular Dynamics Simulation; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D011487:Protein Conformation; D017434:Protein Structure, Tertiary
chemical_list: D020746:Calcium Channels, L-Type; D002147:Calmodulin; C419385:L-type calcium channel alpha(1C)